adding Pythia8 Filter for genparticles HT

[alefisico]

Hi,

I need to include this filter for the generation of our signal. It only calculates the HT of generated particles from pythia8. I think for the actual generation I need it to be backported to 7_1_X ( the release that will actually be used) and 7_6_X as the release the output will be in.

Please let me know if you have any question.

[cmsbuild]

A new Pull Request was created by @alefisico (Alejandro Gomez Espinosa) for CMSSW_8_0_X.

It involves the following packages:

GeneratorInterface/GenFilters

@vciulli, @covarell, @thuer, @cmsbuild, @bendavid, @davidlange6, @govoni can you please review it and eventually sign? Thanks.
@mkirsano this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

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[bendavid]

The filter is only needed in 80x and 71x (you don't need it in 76x, since only the digi-reco will be done there)

If you only use the status 23 particles, then you will end up with ~exactly the same result as if you just applied the HT cuts at the madgraph level.

Instead I think what you will want to do is run the genparticle and genjet producers and then filter on the HT of the GenJet collection (This is as close as you can get to reconstruction-level jets)

[alefisico]

Hi Josh, I cannot applied an HT cut at madgraph level since the quarks coming from the stops are not generated in madgraph but in pythia8. I tried to apply an HT cut in madgraph but it is applied only to the extra partons. That is the reason I have to use this filter after pythia8.

[bendavid]

Ah ok yes you're right. If you do it like this then indeed the HT calculation will include the stop decay products.

So indeed what is here should be ok and does address the original issue.

On the other hand, since you already have to run pythia, you COULD do the filtering at genjet level, and this would be closer to the kinematics of the reconstructed jets.

Let me know if you want to try that or if you're happy with what you have here, in which case I'll just merge it.

[alefisico]

yes, we checked it with genJets. You can see the plot here, where I am comparing the samples without extra partons, with extra partons and without this filter and with this filter, using AK4 genJets:

basically, by applying this HT filter I think we are fine.

[bendavid]

+1

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/9893/console

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_0_X IBs after it passes the integration tests. This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @Degano, @smuzaffar

[cmsbuild]

+1
Tested at: 275f393
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12516/9893/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12516/9893/summary.html

[davidlange6]

+1